Smart multi-level RF pulsing methods

Abstract

Methods of operating a plasma enhanced substrate processing system using multi-level pulsed RF power are provided herein. In some embodiments, a method of operating a plasma enhanced substrate processing system using multi-level pulsed RF power includes providing a first multi-level RF power waveform to a process chamber, the first multi-level RF power waveform having at least a first power level, a second power level, and a third power level, providing, after a first delay period, a second multi-level RF power waveform to the process chamber, the second multi-level RF power waveform having at least a first power level, a second power level, and a third power level, and processing the substrate using the first multi-level RF power waveform and the second multi-level RF power waveform to produce a features on the substrate have an aspect ratio of greater than 60:1 while maintaining an etch rate of greater than 170 nm/min.

The invention claimed is: 
     
       1. A method for processing a substrate in a plasma enhanced substrate processing system using multi-level pulsed RF power, comprising:
 providing, from a first RF generator, a first multi-level RF power waveform to a process chamber, the first multi-level RF power waveform having at least a first power level during a first pulse duration, a second power level during a second pulse duration, and a third power level during a third pulse duration, wherein the first, second and third power levels of the first multi-level RF power waveform are different from each other; 
 providing, from a second RF generator and_after a first delay period, a second multi-level RF power waveform to the process chamber, the second multi-level RF power waveform having at least a first power level during a first pulse duration, a second power level during a second pulse duration, and a third power level during a third pulse duration, wherein the first, second and third power levels of the second multi-level RF power waveform are different from each other; and 
 processing the substrate using the first multi-level RF power waveform and the second multi-level RF power waveform to produce features on the substrate having an aspect ratio of greater than 60:1 while maintaining an etch rate of greater than 170 nm/min. 
 
     
     
       2. The method of  claim 1 , wherein the features produced on the substrate have an aspect ratio of greater than 60:1 while maintaining an etch rate of at least 240 nm/min. 
     
     
       3. The method of  claim 1 , wherein the first power level of the first multi-level RF power waveform is a high power level, the second power level of the first multi-level RF power waveform is a low power level that is lower than the first power level of the first multi-level RF power waveform, and the third power level of the first multi-level RF power waveform is a zero power level. 
     
     
       4. The method of  claim 3 , wherein the first power level of the second multi-level RF power waveform is a high power level, the second power level of the second multi-level RF power waveform is a low power level that is lower than the first power level of the second multi-level RF power waveform, and the third power level of the second multi-level RF power waveform is a zero power level. 
     
     
       5. The method of  claim 1 , further comprising:
 providing, from a third RF generator and after a second delay period, a third multi-level RF power waveform to the process chamber, the third multi-level RF power waveform having at least a first power level during a first pulse duration and a second power level during a second pulse duration, wherein the first, second and third power levels of the third multi-level RF power waveform are different from each other. 
 
     
     
       6. The method of  claim 5 , wherein the first multi-level RF power waveform and the third multi-level RF power waveform are synchronized. 
     
     
       7. The method of  claim 5 , wherein the first multi-level RF power waveform, the second multi-level RF power waveform are synchronized, and the third multi-level RF power waveform are synchronized. 
     
     
       8. The method of  claim 5 , wherein one of the first, second and third power levels of each of the first, second, and third multi-level RF power waveforms is a zero power level. 
     
     
       9. The method of  claim 5 , wherein a duration of time that each of the first, second and third power levels of the first multi-level RF power waveform are applied are different from each other. 
     
     
       10. The method of  claim 5 , wherein a duration of time that each of the first, second and third power levels of the second multi-level RF power waveform are applied are different from each other. 
     
     
       11. The method of  claim 5 , wherein a duration of time that each of the first, second and third power levels of the third multi-level RF power waveform are applied are different from each other. 
     
     
       12. The method of  claim 5 , wherein first multi-level RF power waveform is a source RF signal, and the second and third multi-level RF power waveforms are RF bias signals. 
     
     
       13. The method of  claim 1 , wherein the substrate is processed using a Reactive Ion Etch (RIE) process. 
     
     
       14. The method of  claim 1 , wherein processing the substrate using the multi-level pulsed RF power produces a mask selectivity of greater than 5:1. 
     
     
       15. The method of  claim 1 , wherein processing the substrate using the multi-level pulsed RF power produces reduced profile bowing effects having a delta CD less than 20 nm. 
     
     
       16. A non-transitory computer readable medium having instructions stored thereon that, when executed, cause a method of operating a plasma enhanced substrate processing system using multi-level pulsed RF power to be performed, the method comprising:
 providing, from a first RF generator, a first multi-level RF power waveform to a process chamber, the first multi-level RF power waveform having at least a first power level during a first pulse duration, a second power level during a second pulse duration, and a third power level during a third pulse duration, wherein the first, second and third power levels of the first multi-level RF power waveform are different from each other; 
 providing, from a second RF generator and after a first delay period, a second multi-level RF power waveform to the process chamber, the second multi-level RF power waveform having at least a first power level during a first pulse duration, a second power level during a second pulse duration, and a third power level during a third pulse duration, wherein the first, second and third power levels of the second multi-level RF power waveform are different from each other; and 
 processing the substrate using the first multi-level RF power waveform and the second multi-level RF power waveform to produce feature on the substrate having an aspect ratio of greater than 60:1 while maintaining an etch rate of greater than 170 nm/min. 
 
     
     
       17. A method for processing a substrate in a plasma enhanced substrate processing system using multi-level pulsed RF power, comprising:
 providing, from a first RF generator, a first multi-level RF power waveform to a process chamber, the first multi-level RF power waveform having at least a first power level during a first pulse duration, a second power level during a second pulse duration, and a third power level during a third pulse duration, wherein the first, second and third power levels of the first multi-level RF power waveform are different from each other; 
 providing, from a second RF generator and after a first delay period, a second multi-level RF power waveform to the process chamber, the second multi-level RF power waveform having at least a first power level during a first pulse duration, a second power level during a second pulse duration, and a third power level during a third pulse duration, wherein the first, second and third power levels of the second multi-level RF power waveform are different from each other; 
 providing, from a third RF generator and after a second delay period, a third multi-level RF power waveform to the process chamber, the third multi-level RF power waveform having at least a first power level during a first pulse duration and a second power level during a second pulse duration, wherein the first, second and third power levels of the third multi-level RF power waveform are different from each other; and 
 processing the substrate using the first multi-level RF power waveform and the second multi-level RF power waveform to produce features on the substrate having an aspect ratio of greater than 60:1 while maintaining an etch rate of greater than 170 nm/min, wherein processing the substrate using the multi-level pulsed RF power produces a mask selectivity of greater than 5:1 and reduced profile bowing effects having a delta CD less than 20 nm. 
 
     
     
       18. The method of  claim 17 , wherein the substrate is processed using a Reactive Ion Etch (RIE) process. 
     
     
       19. The method of  claim 17 , wherein the features produced on the substrate have an aspect ratio of greater than 60:1 while maintaining an etch rate of at least 240 nm/min. 
     
     
       20. The method of  claim 19 , wherein a duration of time that each of the first, second and third power levels of the third multi-level RF power waveform are applied are different from each other.